1. Field of the Invention
The present invention relates to a composite charged particle beam apparatus which integrates a plurality of charged particle beam columns, and a sample processing and observing method.
2. Background Art
In order to obtain useful knowledge from observation using a transmission electron microscope (TEM), it is necessary to process a sample which is an observed object to form a very thin lamella (a TEM lamella) which has the thickness of about several tens of nanometers. In order to form such a lamella, a plurality of methods is used, and, among them, a method of using a focused ion beam (FIB) apparatus is typically widely used. The TEM lamella necessarily has a thin portion which is thin enough for the electron beam to be transmitted or thinner, but is preferably as thin over as wide a range as possible. For this reason, when the TEM lamella is formed using the FIB apparatus, there is a need to process the rear surface and the front surface of the lamella in parallel. In addition, in addition to a case where a uniform material is observed using the TEM, in a case where defects, foreign material, a specific local structure, or the like is desired to be observed, there is a need to form a lamella with a thickness of several tens of nanometers while leaving the observed object inside the lamella.
In order to treat these needs, an example is disclosed in which a lamella which is a processed object is easily observed by combining a scanning electron microscope (SEM) and the FIB and a lamella having a high parallelism can be processed by tilting the sample lamella (for example, refer to JP-A-H4-76437).
However, in the disclosed example, since it is necessary to secure a space for installing a sample and a stage mechanism for placing and moving the sample, the SEM and the FIB are disposed with a pinching angle smaller than 90 degrees and the SEM and the FIB are disposed further to the upper side than the surface of the sample. In the case of such a disposition, a size of the sample or the degree of freedom of the disposition is secured, whereas, as shown in FIG. 14, a distance (working distance) between the SEM and the sample cannot be reduced by fixed amount or more. Typically, a high performance SEM column is increased in characteristics including resolution and enables finer observations as the working distance becomes shorter. An improvement in observation capability is essential for forming a highly-sophisticated TEM sample, and thus there is a demand for methods for reducing the working distance of the SEM. Also, in JP-A-H4-76437, a method for forming a lamella having a high parallelism by tilting the sample is disclosed, but a specific mechanism for efficiently and accurately tilting a sample in an actual apparatus configuration is not disclosed.